Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

591
FXUS63 KLOT 222342
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
642 PM CDT Mon Jun 22 2026

.KEY MESSAGES...

- Dangerous swimming conditions at Lake Michigan beaches through
  tonight.

- Chance of thunderstorms returns Wednesday with periodic, but
  low chances for the end of the week into the weekend.

- Warmer and more humid conditions expected early next week.

&&

.DISCUSSION...
Issued at 132 PM CDT Mon Jun 22 2026

Northeast winds will gust into the 25 mph range through sunset
this evening over land and remain gusty into tonight over Lake
Michigan, allowing for high waves and dangerous swimming
conditions at Lake Michigan beaches. There may be a short period
late this afternoon when speeds/gusts increase a bit, before
then slowly diminishing into this evening.

There will be a low chance for an isolated shower or sprinkles
across northwest IL late this afternoon into this evening and
also across northwest IN, also late this afternoon. Have slight
chance pops but most of the area will stay dry.

An upper trough/closed low and associated weak surface low will
move across the Great Lakes region Wednesday into Thursday. This
will bring the next chance of showers and scattered
thunderstorms to the local area on Wednesday. Still some timing
differences for how soon this activity may reach the cwa, with
some of the models bringing precip into the northern cwa around
daybreak Wednesday morning. Additional development is possible
as a cold front moves across the area on Wednesday though low
confidence for coverage/timing. This front is then expected to
move to central IL/central IN by Thursday morning as another
wave moves east, possibly bringing showers and thunderstorms
along the general vicinity of the frontal boundary. Models then
show another wave for Thursday night into Friday, in the same
general area. While there are periodic thunderstorm chances for
the end of the week, there will also be many dry hours,
especially for areas north of I-80.

Additional precip chances Friday into Saturday will signal a
pattern change to warmer and more humid conditions as an upper
ridge builds northeast into the Great Lakes region. As trends
appear now, the best chance for thunderstorms may be in the
Saturday evening through Sunday afternoon time period as the
ridge builds northeast. Once it does, high temps by early next
week look to reach the upper 80s/lower 90s along with dewpoints
in the lower/mid 70s. cms

&&

.AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 642 PM CDT Mon Jun 22 2026

No significant aviation forecast concerns for the 00Z TAFs.

Terminals reside in a region of north-northeast surface flow,
southeast of an area of surface high pressure across Manitoba,
western Ontario and the upper Mississippi Valley. Winds
currently around 15 kts will diminish with sunset, and will
remain light northerly (light and variable at KDPA/KRFD farther
to the west) overnight. Winds will turn more northeast with
mixing after sunrise Tuesday, though will not be quite as
breezy as the surface high pressure ridge edges eastward. A
lake-assist will likely provide speeds around 10 kts for
KORD/KMDW and KGYY by midday/afternoon, with winds eventually
turning more easterly late in the day before becoming light
southeast Tuesday evening.

Otherwise, VFR conditions are expected through the period.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement until 4 AM CDT Tuesday for ILZ006-
     ILZ103-ILZ104.

IN...Beach Hazards Statement until 4 AM CDT Tuesday for INZ001-
     INZ002.

LM...Small Craft Advisory until 1 AM CDT Tuesday for the IL
     nearshore waters.

     Small Craft Advisory until 4 AM CDT Tuesday for the IN
     nearshore waters.

&&

$$

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